package pub.wkq.start;

public abstract class Duck {
    public void quack() {
        System.out.println("嘎嘎叫！ ");
    }
    public void swim() {
        System.out.println("戏水！");
    }
    public void fly() {
        System.out.println("飞翔！");
    }
    public abstract void display();
}
